Hi NJC, thanks for your thoughts. Other researchers like AQR have done similar analysis and also concluded that leverage played a large role in BRK's outperformance. We could add leverage as a factor directly, but indirectly capture it via the factor-mimicking portfolio as the factor weights can be more than 100%. And yes, Warren Buffett has been harvesting the low volatility factor via investments like KO, which requires leverage, way before it became popular. He is one of a kind.